Help - wind instrument

Hi all,

I have a Navman Wind 3100 for the past 3 years, and generally I am happy with it. Lately though I suspect the measurements are kind of low - I see white caps all around but the thing only shows 17 kts of wind...

So, two questions for the knowlegeable people:
1) Although a manual does not say anything, should the rotating masthead unit be oiled or cleaned periodically?
2) Any cjance someone has a hand-held anemometer that I can borrow to calibrate myt instrument? I know people recommend to calibrate it by the boat speed in a windless day by motoring - there is always SOME wind here on the bay...

Thanks,
Stanly

White caps in 17kts sounds right to me but it could depend on the fetch. A hand anemometer will not help you calibrate the unit unless you climb the mast. Wind on the surface can vary greatly from the wind aloft. Water and land cause friction so it may be lower down on the deck of your boat. Maybe compare your reading with some friend's to see how they compare.

I am unsure about the Navman but I think most have sealed bearings and when they go, the cups stop spinning. Check your manual.

White caps above 15 knots sounds right to me too.